/* -*- mode: c; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
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/* vi: set ts=8 sw=8 sts=8: */
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/*************************************************************************/ /*!
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@File debugfs_dma_buf.c
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@Codingstyle LinuxKernel
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@Copyright Copyright (c) Imagination Technologies Ltd. All Rights Reserved
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@License Dual MIT/GPLv2
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The contents of this file are subject to the MIT license as set out below.
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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Alternatively, the contents of this file may be used under the terms of
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the GNU General Public License Version 2 ("GPL") in which case the provisions
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of GPL are applicable instead of those above.
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If you wish to allow use of your version of this file only under the terms of
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GPL, and not to allow others to use your version of this file under the terms
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of the MIT license, indicate your decision by deleting the provisions above
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and replace them with the notice and other provisions required by GPL as set
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out in the file called "GPL-COPYING" included in this distribution. If you do
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not delete the provisions above, a recipient may use your version of this file
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under the terms of either the MIT license or GPL.
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This License is also included in this distribution in the file called
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"MIT-COPYING".
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EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) THE SOFTWARE IS
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PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
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BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
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PURPOSE AND NONINFRINGEMENT; AND (B) IN NO EVENT SHALL THE AUTHORS OR
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COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/ /**************************************************************************/
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#include "debugfs_dma_buf.h"
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#if defined(DEBUGFS_DMA_BUF) && defined(CONFIG_DEBUG_FS)
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#include <linux/kernel.h>
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#include <linux/debugfs.h>
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#include "kernel_compatibility.h"
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static struct dentry *g_debugfs_dentry;
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static struct dma_buf *g_dma_buf;
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static ssize_t read_file_dma_buf(struct file *file, char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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size_t istart = *ppos / PAGE_SIZE, iend, i = istart;
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ssize_t wb = 0, res = 0;
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struct dma_buf *dma_buf = g_dma_buf;
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int err;
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if (!dma_buf)
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goto err_out;
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/* Inc the ref count for the time we use it in this function. */
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get_dma_buf(dma_buf);
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/* End of buffer? */
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if (*ppos >= dma_buf->size)
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goto err_put;
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/* Calculate the number of pages we need to process based on the
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* remaining dma buffer size or the available um buffer size. */
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iend = istart + min((size_t)(dma_buf->size - *ppos), count) / PAGE_SIZE;
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res = dma_buf_begin_cpu_access(dma_buf, DMA_FROM_DEVICE);
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if (res)
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goto err_put;
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/* dma_buf_kmap only allows mapping one page, so we have to loop until
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* the um buffer is full. */
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while (i < iend) {
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loff_t dummy = 0; /* We ignore that */
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void *map = dma_buf_kmap(dma_buf, i);
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if (!map) {
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res = -EFAULT;
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goto err_access;
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}
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/* Read PAGE_SIZE or the remaining buffer size worth of
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* data. Whichever is smaller. */
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res = simple_read_from_buffer(&user_buf[wb], count - wb,
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&dummy, map,
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min((size_t)PAGE_SIZE,
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(size_t)(dma_buf->size - *ppos)));
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dma_buf_kunmap(dma_buf, i, map);
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if (res < 0)
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goto err_access;
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wb += res;
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*ppos += res;
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++i;
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}
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res = wb;
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err_access:
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do {
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err = dma_buf_end_cpu_access(dma_buf, DMA_FROM_DEVICE);
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} while (err == -EAGAIN || err == -EINTR);
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err_put:
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dma_buf_put(dma_buf);
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err_out:
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return res;
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}
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static const struct file_operations fops_dma_buf = {
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.open = simple_open,
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.read = read_file_dma_buf,
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.llseek = default_llseek,
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};
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int debugfs_dma_buf_init(const char *name)
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{
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int err = 0;
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g_debugfs_dentry = debugfs_create_file(name, S_IRUSR, NULL,
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NULL, &fops_dma_buf);
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if (IS_ERR(g_debugfs_dentry)) {
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err = PTR_ERR(g_debugfs_dentry);
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g_debugfs_dentry = NULL;
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goto err_out;
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}
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err_out:
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return err;
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}
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void debugfs_dma_buf_deinit(void)
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{
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debugfs_remove(g_debugfs_dentry);
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}
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void debugfs_dma_buf_set(struct dma_buf *dma_buf)
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{
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struct dma_buf *old_dma_buf = g_dma_buf;
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if (dma_buf)
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get_dma_buf(dma_buf);
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g_dma_buf = dma_buf;
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if (old_dma_buf)
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dma_buf_put(old_dma_buf);
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}
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#else /* defined(DEBUGFS_DMA_BUF) && defined(CONFIG_DEBUG_FS) */
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int debugfs_dma_buf_init(const char *name)
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{
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return 0;
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}
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void debugfs_dma_buf_deinit(void)
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{
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}
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void debugfs_dma_buf_set(struct dma_buf *dma_buf)
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{
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}
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#endif /* defined(DEBUGFS_DMA_BUF) && defined(CONFIG_DEBUG_FS) */
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